Synthesis and X‐Ray Single Crystal Structure of Two New Copper Complexes with the Redox Active Ligand 1,10‐Phenanthroline‐5,6‐dione

The synthesis and the crystal structures of the complexes [Cu(L^I)₂](ClO₄) ( 1 ) and [Cu(L^I)(CH₃CN)₂(ClO₄)₂] ( 2 ) are reported. 1 crystallizes in the monoclinic space group C2/c with the unit cell dimensions a = 13.169(4), b = 12.289(3), c = 14.732(3) Å, β = 109.03(2)° and Z = 4. Copper(I) is coordinated to four N atoms of the two 1,10‐Phenanthroline‐5,6‐dione (L^I) ligands with a two‐fold axis passing between the ligands. The copper(II) compound 2 crystallizes in the orthorhombic space group Pbn2₁ with unit cell dimensions of a = 7.498(5), b = 23.492(7), c = 12.363(4) Å and Z = 4. Copper(II) coordination can be described as a distorted octahedron with the N donor atoms of one L^I ligand and of two molecules of CH₃CN occupying the equatorial positions completed by two oxygen atoms of the two perchlorate molecules in the axial positions.     

Square‐Wave Voltammetry of the Molybdenum‐1,10 Phenanthroline‐Fulvic Acids Complex: Redox Kinetics Measurements

The reduction process of molybdenum in the presence of fulvic acids and phenanthroline was investigated by square-wave voltammetry (SWV). The mixed-ligand complex of molybdenum exhibits a pronounced tendency to adsorb onto the mercury electrode surface. The electrode reaction proceeds as a surface process in which both components of the redox couple are firmly confined to the electrode surface. The kinetics of the electrode reaction is studied utilizing the properties of “split SW peaks” and “quasireversible maximum”. The kinetic parameters obtained with two different square-wave voltammetric methods are in good agreement. In 0.5 mol/L NaCl solution with pH 2.5 the kinetic parameters are: standard rate constant k_s=8±2 s⁻¹, cathodic electron transfer coefficient α=0.41±0.05, and number of exchanged electrons n=2. The SW kinetic measurements are confirmed by cyclic voltammetric method.     

Cu(II) and Ni(II)‐1,10‐phenanthroline‐ 5,6‐dione‐amino acid ternary complexes exhibiting pH‐sensitive redox properties

Syntheses, and electrochemical properties of two novel complexes, [Cu(phendio)(L ‐Phe)(H₂O)](ClO₄) ·H₂O (1) and [Ni(phendio)(Gly)(H₂O)](ClO₄)·H₂O (2) (where phendio = 1,10‐phenanthroline‐5,6‐dione, L ‐Phe = L ‐phenylalanine, Gly = glycine), are reported. Single‐crystal X‐ray diffraction results of (1) suggest that this complex structure belongs to the orthorhombic crystal system. The electrochemical properties of free phendio and these complexes in phosphate buffer solutions in a pH range between 2 and 9 have been investigated using cyclic voltammetry. The redox potential of these compounds is strongly dependent on the proton concentration in the range of ? 0.3–0.4 V vs SCE (saturated calomel reference electrode). Phendiol reacts by the reduction of the quinone species to the semiquinone anion followed by reduction to the fully reduced dianion. At pH lower than 4 and higher than 4, reduction of phendio proceeds via 2e^?/3H⁺ and 2e^?/2H⁺ processes. For complexes (1) and (2), being modulated by the coordinated amino acid, the reduction of the phendio ligand proceeds via 2e^?/2H⁺ and 2e^?/H⁺ processes, respectively. Copyright © 2006 John Wiley & Sons, Ltd.     

Synthesis,Characterization and X‐ray Crystal Structure of a Chromium(III) Complex Obtained from a Proton‐Transfer Compound Containing 1,10‐Phenanthroline‐2,9‐dicarboxylic Acid and 2,6‐Pyridinediamine

The novel 1,10‐phenanthroline‐2,9‐dicarboxylate containing Chromium(III) complex, (pydaH)[Cr(phendc)₂] · 5H₂O, was synthesized using proton‐transfer compound LH₂, (pydaH₂)²⁺(phendc)^2?, (pyda: 2,6‐pyridinediamine; phendcH₂: 1,10‐phenanthroline‐2,9‐dicarboxylic acid) and thoroughly characterized by elemental analysis, IR spectroscopy, X‐ray crystallography and cyclic voltammetry. The complex crystallizes in the monoclinic space group P2₁/n with four formula units in the unit cell. The unit cell dimensions are: a = 13.962(3) Å, b = 14.529(3) Å, c = 16.381(3) Å and β = 106.691(4)°. In this complex, 1,10‐phenanthroline‐2,9‐dicarboxylate acts as a tridentate ligand and the lattice is composed of anionic hexacoordinated complex, [Cr(phendc)₂]^?, 2,6‐pyridiniumdiamine counter ion, (pydaH)⁺, and five lattice water molecules. Crystallographic characterization revealed that the resulting supramolecular structure is strongly stabilized by complicated network of hydrogen bonds between the crystallization water molecules, counter ion and both coordinated and uncoordinated carboxylate groups. There is no relevant π‐π interaction for this anionic complex between pyda or phendc moieties. The electrochemical studies indicated over potential for both the cathodic and anodic peaks of the complex with respect to the free Cr³⁺ ion, as a consequence of the energy requirement for rearrangement of the ligand at electrode surface.     

A three‐dimensional coordination polymer based on the Zn4(μ3‐OH)2 unit: poly[[(μ4‐benzene‐1,4‐dicarboxylato)bis(μ3‐benzene‐1,4‐dicarboxylato)bis(μ3‐hydroxido)bis(1,10‐phenanthroline‐5,6‐dione)tetrazinc] dihydrate]

The title compound, {[Zn₄(C₈H₄O₄)₃(OH)₂(C₁₂H₆N₂O₂)₂]·2H₂O}_n, has been prepared hydrothermally by the reaction of Zn(NO₃)₂·6H₂O with benzene‐1,4‐dicarboxylic acid (H₂bdc) and 1,10‐phenanthroline‐5,6‐dione (pdon) in H₂O. In the crystal structure, a tetranuclear Zn₄(OH)₂ fragment is located on a crystallographic inversion centre which relates two subunits, each containing a [ZnN₂O₄] octahedron and a [ZnO₄] tetrahedron bridged by a μ₃‐OH group. The pdon ligand chelates to zinc through its two N atoms to form part of the [ZnN₂O₄] octahedron. The two crystallographically independent bdc²⁻ ligands are fully deprotonated and adopt μ₃‐κO:κO′:κO′′ and μ₄‐κO:κO′:κO′′:κO′′′ coordination modes, bridging three or four Zn^II cations, respectively, from two Zn₄(OH)₂ units. The Zn₄(OH)₂ fragment connects six neighbouring tetranuclear units through four μ₃‐bdc²⁻ and two μ₄‐bdc²⁻ ligands, forming a three‐dimensional framework with uninodal 6‐connected α‐Po topology, in which the tetranuclear Zn₄(OH)₂ units are considered as 6‐connected nodes and the bdc²⁻ ligands act as linkers. The uncoordinated water molecules are located on opposite sides of the Zn₄(OH)₂ unit and are connected to it through hydrogen‐bonding interactions involving hydroxide and carboxylate groups. The structure is further stabilized by extensive π–π interactions between the pdon and μ₄‐bdc²⁻ ligands.     

Synthesis,Characterization, and Crystal Structure of a Chromium(III)‐Complex Containing 2,6‐Pyridinedicarboxylic Acid and 1,10‐Phenanthroline

The reaction of solution 2,6‐pyridinedicarboxylic acid and 1,10‐phenanthroline ( 1 ) with CrCl₃·6H₂O led to the complex [Cr(phen)(pydc)(H₂O)][Cr(pydc)₂]·4H₂O ( 2 ) (phen is 1,10‐phenanthroline and pydcH₂ is 2,6‐pyridinedicarboxylic acid). 2 was characterized by elemental analysis, IR spectroscopy and single‐crystal structure determination. Crystal data for 2 at ?80 °C: triclinic, space group , a = 818.5(1), b = 1492.2(1), c = 1533.6(2) pm, α = 76.45(1)°, β = 84.22(1)°, γ = 77.99(1)°, Z = 2, R₁ = 0.0416.     

Preparation of an Electrode Modified with an Electropolymerized Film as a Mediator of NADH Oxidation and Its Application in an Ethanol/O2 Biofuel Cell

This paper reports a novel mediator for the oxidation of β‐nicotinamide adenine dinucleotide (NAD⁺/NADH), an electropolymeric film (pAPRu) of [Ru(NH₂‐phen)₃]²⁺. A pAPRu‐modified electrode was prepared via electropolymerization and exhibited catalytic activity toward the electrochemical oxidation of NADH due to the imine moieties of pAPRu. The electrochemical oxidation of ethanol was observed using an alcohol dehydrogenase (ADH)‐immobilized electrode. A compartmentless ethanol/O₂ biofuel cell composed of an ADH anode and a bilirubin oxidase cathode was constructed. The maximum current density and the maximum power density of the biofuel cell were 190 µA cm^?2 and 31 µW cm^?2 (at 0.29 V), respectively.     

Application of the Fe3O4@1,10‐phenanthroline‐5,6‐diol@Mn nano‐catalyst for the green synthesis of tetrazoles and its biological performance

The Fe₃O₄ magnetic particles were modified with 1,10‐phenanthroline‐5,6‐diol (Phen) and the related Mn complex (Fe₃O₄@Phen@Mn) synthesized as a heterogeneous catalyst to be used for the one‐pot three‐component synthesis of various tetrazoles. The catalysts were characterized by several methods, such as the elemental analysis, FT‐IR, X‐ray powder diffraction, dispersive X‐ray spectroscopy, scanning electron microscopy, transmission electron microscopy, dynamic light scattering, thermogravimetric‐differential thermal analysis, vibrating sample magnetometer and X‐ray photoelectron spectroscopy. In addition, the antioxidant and antibacterial activities of the catalyst and its Phen ligand were in vitro screened with 2,2‐diphenyl‐1‐picrylhydrazyl by free radical scavenging methods. Results showed that the synthesized compounds possess strong antioxidant activity (IC50; 0.172  ±  0.005 mg ml^?1) as well as a good antibacterial potential in comparison to standards.     

Syntheses,Structures, Photoluminescence,and Magnetism of a Series of Discrete Lanthanide Complexes based on 2,5‐Dichlorobenzoate and 1,10‐Phenanthroline

The syntheses and crystal structures of eight lanthanide complexes with formula [Ln(2,5‐DCB)_x(phen)_y] are reported, which are characterized via single‐crystal, powder X‐ray diffraction, elemental analysis, IR spectroscopy, thermogravimetric analysis, photoluminescence measurement, and DC/AC magnetic measurement. These eight complexes are isostructural, and possess a discrete dinuclear structure. The adjacent dinuclear molecules are linked by the hydrogen bonding interactions into a one‐dimensional (1D) supramolecular chain. The neighboring 1D chains are further extended into a two‐dimensional (2D) supramolecular layer by the π–π stacking interactions. The photoluminescent properties of complexes 1 (Nd^III), 2 (Sm^III), 3 (Eu^III), 5 (Tb^III), 6 (Dy^III), and 8 (Yb^III) were investigated. Magnetic investigations also reveal the presence of ferromagnetic interactions in complexes 4 (Gd^III), 6 (Dy^III), and 7 (Er^III). Additionally, complex 6 (Dy^III) demonstrates field‐induced slow magnetic relaxation behavior.     

Sol—Gel Derived Carbon Ceramic Electrode Bulk—Modified with Tris（1,10—phenanthroline—5,6—dione） iron （Ⅱ）Hexafluorophosphate and Its Use as an Amperometric Iodate Sensor

A surface‐renewable tris(1, 10‐phenanthroline‐5, 6‐dione) iron (D) hexafluorophosphate (FePD) modified carbon ceramic electrode was constructed by dispersing FePD and graphite powder in methyltrimethoxysilane (MTMOS) based gels. The FePD‐modified electrode presented pH‐dependent voltammetric behavior, and its peak currents were diffusion‐controlled in 0.1 mol/L Na₂SO₄ + H₂SO₄ solution (pH = 0.4). In the presence of iodate, dear electrocatalytic reduction waves were observed and thus the chemically modified electrode was used as an amperometric sensor for iodate in common salt. The linear range, sensitivity, detection limit and response time of the iodate sensor were 5 × 10^?6–1 × 10^?2 mol/L, 7.448 μA·L/ mmol, 1.2 × 10^?6 mol/L and 5 s, respectively. A distinct advantage of this sensor is its good reproducibility of surface‐renewal by simple mechanical polishing.     

Construction of L‐Lysine Sensor by Layer‐by‐Layer Adsorption of L‐Lysine 6‐Dehydrogenase and Ferrocene‐Labeled High Molecular Weight Coenzyme Derivative on Gold Electrode

A ferrocene‐labeled high molecular weight coenzyme derivative (PEI‐Fc‐NAD) and a thermostable NAD‐dependent L ‐lysine 6‐dehydrogenase (LysDH) from thermophile Geobacillus stearothermophilus were used to fabricate a reagentless L ‐lysine sensor. Both LysDH and PEI‐Fc‐NAD were immobilized on the surface of a gold electrode by consecutive layer‐by‐layer adsorption (LBL) technique. By the simple LBL method, the reagentless L ‐lysine sensor, with co‐immobilization of the mediator, coenzyme, and enzyme was obtained, which exhibited current response to L ‐lysine without the addition of native coenzyme to the analysis system. The amperometric response of the sensor was dependent on the applied potential, bilayer number of PEI‐Fc‐NAD/LysDH, and substrate concentration. A linear current response, proportional to L ‐lysine concentration in the range of 1–120 mM was observed. The response of the sensor to L ‐lysine was decreased by 30% from the original activity after one month storage.     

Controllable ring‐opening copolymerization of L‐lactide and (3S)‐benzyloxymethyl‐(6S)‐methyl‐morpholine‐2,5‐dione initiated by a biogenic compound creatinine acetate

Ring‐opening copolymerization (ROCP) of L ‐lactide (L ‐LA) and (3S)‐benzyloxymethyl‐(6S)‐methyl‐morpholine‐2,5‐dione [(3S, 6S)‐BMMD] initiated by creatinine acetate, a biogenic organic compound, was performed in the bulk at 130 °C. The copolymerization was well controlled as evidenced by that both the measured values of number‐average molecular weight (M_n,NMR(OH) and M_n,NMR(COOH)) and serine molar fraction (F_Bz.ser) of synthesized copolymers were close to the corresponding theoretical values; and that the higher isotacticity of synthesized copolymers (85–86%) and lower racemization degree of the ROCP. After removing O‐benzyls of the copolymers with Et₃SiH/Et₃N/CH₂Cl₂ under catalysis of PdCl₂, functional biodegradable copolymers of L ‐lactic acid (L ‐Lac) and L ‐Ser with designed molar fraction of serine (F_ser 1.35%, 3.57%, 5.41%), narrow molecular weight distribution (polydispersity index 1.10–1.36), and improved hydrophilicity (θ_stat 82.3–89.6°) were finally obtained. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Diels–Alder reaction of 2,7‐dichloroquinoline‐5,8‐dione with a thiazole o‐quinodimethane. Assignment of the regiochemistry by 1H–13C HMBC correlations

The Diels–Alder reaction between a thiazole o‐quinodimethane and 4,6‐dichloroquinoline‐5,8‐dione gave 6‐chloro‐9‐azaanthra[2,3‐b]thiazole‐5,10‐dione as a single regioisomer. Its structure was assigned by 2D ¹H–¹³C HMBC short‐ and long‐range correlations. Measuring the spectra in CF₃CO₂D indicated that both nitrogen atoms of pyridine and thiazole rings are deuterated. Copyright © 2001 John Wiley & Sons, Ltd.     

Determination of paroxetine in serum treated with simple pretreatment by pre‐column high‐performance liquid chromatography using 4‐(5,6‐dimethoxy‐2‐phthalimidinyl)‐2‐methoxyphenylsulfonyl chloride as a fluorescent labeling reagent

The therapeutic drug monitoring of paroxetine could be used to optimize the pharmacological treatment of depressed patients. A simple and sensitive high‐performance liquid chromatography procedure was developed for the determination of paroxetine in serum. After simple pretreatment of serum (50 μL) with acetonitrile and o‐phthalaldehyde, paroxetine was derivatized with 4‐(5,6‐dimethoxy‐2‐phthalimidinyl)‐2‐methoxyphenylsulfonyl chloride at 70°C for 20 min in borate buffer (0.1 mol/L, pH 8.0) to produce a fluorescent product. The derivative was separated on a reversed‐phase column at 40°C for stepwise elution with (A) acetic acid (10 mmol/L) and (B) acetonitrile. The flow rate was 1.0 mL/min. The fluorescence intensity was monitored at excitation and emission wavelengths of 320 and 400 nm, respectively. The within‐day and day‐to‐day relative standard deviations were 3.0–3.4 and 2.7–8.3%, respectively. The detection limit of paroxetine was 8.3 fmol at a signal‐to‐noise ratio of 3. As the proposed method that only requires a small quantity of serum (50 μL) is simple, sensitive and reproducible, it would be useful for clinical and biochemical research as well as drug monitoring. Copyright © 2013 John Wiley & Sons, Ltd.     

Preparation of Polymer Nanofibers Containing Silver Nanoparticles by Using Poly(N‐vinylpyrrolidone)

Summary: Poly(N‐vinylpyrrolidone) (PVP) was used in two methods to prepare polymer nanofibers containing Ag nanoparticles. The first method involved electrospinning the PVP nanofibers containing Ag nanoparticles directly from the PVP solutions containing the Ag nanoparticles. N,N‐Dimethylformamide was used as a solvent for the PVP as well as a reducing agent for the Ag⁺ ions in the PVP solutions. In the second method, poly(vinyl alcohol) (PVA) aqueous solutions were electrospun with 5 wt.‐% of the PVP containing Ag nanoparticles. The Ag nanoparticles were evenly distributed in the PVA nanofibers. PVP containing Ag nanoparticles could be used to introduce Ag nanoparticles to other polymer nanofibers that are miscible with PVP.

TEM image of a PVA nanofiber electrospun with 5 wt.‐% of the PVP containing Ag nanoparticles.     

Preparation of Sb2O3‐loaded Activated Carbon Particle Electrode and Its Electrocatalytic Degradation of Methyl Orange in a Three‐dimensional Electrode Cell

Electrocatalysis on the degradation of methyl orange is investigated using Sb₂O₃‐loaded activated carbon (Sb₂O₃/AC), a new particle electrode. The electrode was prepared by an impregnation method. An orthogonal array with four factors and three levels was selected to carry out the experiment. Electrocatalysis on the degradation of methyl orange through Sb₂O₃/AC was characterized by a series of parameters, including the amount of the particle electrode, the concentration of Na₂SO₄, the cell voltage, and the electrolysis time, and the results were compared with those of a conventional AC particle electrode. The results indicate that calcination temperature has the greatest impact on the catalytic activity of the particle electrode. The optimal conditions for preparing the Sb₂O₃/AC electrode include an 8 mL SbCl₃ solution, 90 min hydrolysis time, 400 °C calcination temperature, and 180 min calcination time. As well, the degradation efficiency of the Sb₂O₃/AC electrode is consistently higher than that of the AC electrode under the same electrolysis conditions. The electrochemical oxidation of methyl orange of both electrodes conformed to pseudo first‐order kinetics, but the rate constant of the Sb₂O₃/AC electrode was 2.29 times that of the AC electrode; this is likely due to the high electrocatalytic activity of the experimental electrode. The electrocatalysis results exhibited the synergetic effects of AC and Sb₂O₃ in the new particle electrode.     

A Novel Strategy for the Preparation of Reactively Compatibilized Polymer Blends with Oligomers Containing α‐Methyl Styrene Units

A novel strategy to prepare reactively compatibilized polymer blends is reported. An oligomer that consists of AMS (α‐methyl styrene) and GMA (glycidyl methacrylate) is initially synthesized. When this oligomer is melt blended with poly(propylene) (PP), the GMA units in the oligomer are successfully grafted onto the PP chain, which is proven by measuring the FT‐IR spectrum of the blended PP. When the oligomer is added to a blend of PP/Ny66, an in‐situ compatibilization occurs, which leads to an increase in torque values during blending, a decrease in crystallinity degree of Ny66, and is observed by SEM images of the resulting blends. The compatibilizing effects of the oligomer are also observed in PP/Ny6 and polyethylene/Ny6 blends. A relevant compatibilization mechanism is proposed.

     

Selective Electroanalysis of Ascorbic Acid Using a Nickel Hexacyanoferrate and Poly(3,4‐ethylenedioxythiophene) Hybrid Film Modified Electrode

The mixed‐valent nickel hexacyanoferrate (NiHCF) and poly(3,4‐ethylenedioxythiophene) (PEDOT) hybrid film (NiHCF‐PEDOT) was prepared on a glassy carbon electrode (GCE) by multiple scan cyclic voltammetry. The films were characterized using atomic force microscopy, field emission scanning electron microscopy, energy dispersive spectroscopy, X‐ray diffraction, and electrochemical impedance spectroscopy (AC impedance). The advantages of these films were demonstrated for the detection of ascorbic acid (AA) using cyclic voltammetry and amperometric techniques. The electrocatalytic oxidation of AA at different electrode surfaces, such as the bare GCE, the NiHCF/GCE, and the NiHCF‐PEDOT/GCE modified electrodes, was determined in phosphate buffer solution (pH 7). The AA electrochemical sensor exhibited a linear response from 5×10⁻⁶ to 1.5×10⁻⁴ M (R²=0.9973) and from 1.55×10⁻⁴ to 3×10⁻⁴ M (R²=0.9983), detection limit=1×10⁻⁶ M, with a fast response time (3 s) for AA determination. In addition, the NiHCF‐PEDOT/GCE was advantageous in terms of its simple preparation, specificity, stability and reproducibility.